PEX is a long established acronym for a cross-linked polyethylene manufactured by cross-linking a high density polyethylene (HDPE) with cross-linking reagents. It is commonly recognized for decades that PEX piping and tubing defines a cross-linked HDPE cross-linked within a range of 65 to 89 percent cross-linkage as determined by ASTMD2765. The term “PEX” and cross-linked polyethylene or cross-linked HDPE as used and applied herein refers to cross-linked high density polyethylene meeting this 65-89 percent cross-linkage standard. PEX is generally manufactured by three different methods of cross-linking HDPE namely the Engles method (PEX-a), the Silane method (PEX-b) and the radiation method (PEX-c), all of which meet the ASTM, WSF & CSA standards. PEX pipe, PEX piping, PEX tubing, PEX, PEX tube, plumb PEX and heat PEX are generally recognized as referring to the same product.
Although PEX piping is referred to as possessing flexible attributes, its flexibility is severely limited because of its cross-linked structure. The PEX cross-linked structure converts the uncross-linked thermoplastic HDPE possessing excellent winding and rewinding flexibility into a thermoset plastic which drastically alters its physical properties imparting an inability to effectively bend around objects, wind or unwind from a common reel. Unlike conventional polyethylene tubing which possess sufficient flexibility to allow the high density polyethylene tubing to be freely bent, wound and unwound from a reel, PEX piping cannot be wound or unwound from a spool or a spool wound form. Excessive bending or abrupt angular bending can collapse or damage the PEX tubular structure. The pronounced 65-89% cross-linkage structure of PEX pipe imparts thermoset characteristics which prevents PEX from being windable about or unwindable from a spool or reel. The inability to effectively wind or unwind PEX becomes further complicated by the fact that the high density polyethylene cross-linkage imparts a spring-like memory character onto the conventionally factory manufactured strapped PEX coils. Thus upon a cutting of the factory bound straps, the PEX coil tends to uncoil into a larger sized coil patterned after its inherent memory properties which creates particular difficulties and tediousness in order to maintain the coil in a suitable form for effectively installing the PEX tubing at the work site. The PEX installer must accordingly undertake extraordinary precautionary measures to maintain the PEX in a manageable form while creating or imparting a new memory character by realigning the PEX coil to match the installation thereof at the work site. Imparting a new memory configuration forcibly realigning the coil involves time and anchoring of the PEX piping a desired installation configuration so as to establish the newly acquired memory configuration for the PEX piping. This is most difficult because the coiled PEX piping inherently resists restructuring into an uncoiled form, must be forced into a newly acquired configuration and tends to snarl itself into an unworkable mess if not handled under carefully controlled installation conditions. Thus, the plumbing installation will often require at least two laborers or more depending upon the installation conditions.
It is also conventional to string continuous flexible (PEX) conduit along the floor joists so as to provide the necessary utility systems in new and old constructions. PEX pipe has served as a replacement to copper tubing and piping in various different types of construction. PEX tubing or piping is commercially available in imperial sizes ranging from ¼ inch up to 4 inch size with the ½, ¾, and 1 inch sizes being the most common for residential uses. PEX is commonly used in hydronic radiant heating systems, domestic water piping, insulation for high tension (high voltage) electronic cables, natural gas, off-shore oil applications, chemical transportation, sewage and sludge transportations, etc.
Continuous coils of cross-linked high density polyethylene (PEX) tubing for use in hot and cold water systems are commercially available in 300 and 1000 foot lengths of continuous PEX piping or PEX tubing coils for use by the plumbing contractor. The 300 foot coiled PEX conduits are lighter and easier to handle than the industrialized 1000 foot PEX size and are generally preferred for use especially in the smaller commercial and residential projects. The prepackaged coiled PEX conduits are indexed with footage markings so as to enable a worker to ascertain the remaining amount of coiled PEX conduit and footage actually used at any given construction site. Typically, a 300 foot continuous PEX coil of PEX water tubing (e.g. such as AQUAPEX®, a cross-linked high density polyethylene tubing (PEX) sold and distributed by Wirsbo Company, an Illinois Corp., having a principal business address at 5925 148th Street West, Apply Valley, Minn., often complimented with a hePEX™ coating serving as an added oxygen barrier coating) will be boxed and shipped in a rectangular cardboard box measuring about 32 inches square in widths ranging from 4, 6, and 10 inches in 300 foot lengths respectively for ½″, ¾″, and 1″ diameter tubes. A boxed and cinched strapped 300 foot of ½ inch PEX coil will typically weigh about eighteen pounds, while a ¾ inch diameter packaged PEX coil weighs about 34 pounds and a one inch prepackaged PEX coil weighs about 56 pounds. In contrast a 500 foot prepackaged PEX coil of one inch diameter PEX tubing will weigh about 94 pounds and accordingly packaged in a container of a wider width to accommodate the larger sized coiled PEX conduit size. In conventional practice, the plumbing contractor will either remove or open the top panel flap of the cardboard box so that, after cutting the binding straps, the outermost PEX tubing free-end may then be unwound from the PEX coil. The most typical procedure involves dispensing the uncoiled PEX water tubing from an open top flap of the shipping box which continues until the PEX tubing ultimately rips through the bottom of the box. As the PEX tubing is unwound from the PEX coil, it is then typically strung and secured under physical manipulation to floor joists by conduit or joist staples or by drilling conduit holes through the floor joists so as to provide the necessary PEX conduit for the water supply system. The stringing process typically commences at one of the terminating ends of the water system and then stringing towards the water source or vice versa. With use, dragging the heavy PEX conduit box across floors, such as concrete basement floors, ultimately damages or destroys the shipping container so it is no longer useful to box the unused PEX coil. The coiled PEX water tubing is poorly suited to be dispensed from the original shipping container in this manner. There exists no suitable dispensing device for PEX piping at the work site.
Because of its uniquely intrinsic properties, it is also not an easy task to uncoil the relatively stiff PEX water tubing from the PEX tubing coil while also trying to string the uncoiled tubular PEX conduit through holes bored through floor joists or onto the PEX conduit anchoring or suspending sites. The PEX water tubing becomes considerably more stiffer and less flexible in cold weather because of its unique cross-linked structure. Often, it becomes necessary to interrupt the stringing process to unkink or untangle a snarled PEX coil or to fix a damaged PEX conduit before proceeding any further with the stringing of PEX conduit along the floor joints. If the entanglement becomes too severe, it may become necessary to splice a damaged PEX tube section so as to retain the necessary continuity in the PEX piping or water system. If the PEX conduit container or shipping box fails to contain the coiled PEX conduit, the PEX conduit is prone to errantly uncoil into a tangled mess which then becomes most difficult to manage and string. Invariably, it becomes necessary in normal operations to remove the last 150 feet or so of coiled PEX conduit from the shipping container with the assistance of at least two workers to unravel and uncoil the coiled PEX conduit so that it may be effectively strung onto the floor joists. Under the prior art practices, the entire unreeling procedure is at best tedious and fraught with many difficulties which impede effective stringing of the PEX conduit.
The current system for stringing continuous conduits of PEX water tubing is time consuming and if not done with the most appropriate care, can lead to premature uncoiling of the PEX conduit, damage or splicing of the PEX water tubing or other costly delays. In order to facilitate the unwinding of the coiled PEX tubing, it is often advantageous to have one worker pulling or stringing the PEX water tubing along the stringers or floor joists while another worker tends to the unwinding of the coiled PEX tubing. A procedure or device which would allow a single worker to effectively uncoil the PEX conduit and install the system at the construction site would be of particular value and usefulness.
There accordingly exists a need for a PEX conduit dispensing device which would allow a single worker to effectively unwind and install a PEX conduit system along the floor joist or other suitable mounts. A PEX dispensing device which would uniformly and unerringly unwind the coiled PEX conduit from its coiled structure or source while allowing a single worker to string, staple or thread the required PEX tubing to the anchoring joists as needed would significantly reduce installation costs and reduce damage to the PEX tubing. There also exists a need for a device which more expeditiously establishes a desired new memory configuration to an unwinding PEX coil under the diverse conditions arising at a PEX installation site.